1. Field
This disclosure relates generally to semiconductor processing, and more specifically, to a resistive random access memory (RAM) cell and a method for forming.
2. Related Art
Different types of devices may be used to implement non-volatile memories. For example, one type of non-volatile memory device is a charge storage metal-on-silicon (MOS) device in which the state of the device is based on the charge storage. These types of charge storage devices may store charge in an isolated floating gate, in dielectrics, or in discrete storage devices such as nanocrystals. Another type of non-volatile memory device is a polarity change device, such as a ferroelectric random access memory (FeRAM) device or a magnetoresistive random access memory (MRAM) device, in which the state of the device is based on a polarity of the device. Yet another type of non-volatile memory device is a conductivity change device, such as a phase change random access memory (PCRAM) device, a resistive random access memory (ReRAM) device, or a fuse and anti-fuse device, in which the state of the device is based on the conductivity of the device.
With respect to a resistive RAM (ReRAM) device, the states of the resistive RAM device depend on the resistance of the device. For example, a higher resistance may correspond to a first state and a lower resistance may correspond to a second state. Tight resistance distribution is necessary to achieve multilevel storage capability which can significantly increase the data density. Therefore, it is desirable to improve control over the resistance distribution and to improve data retention for resistive RAM devices.